Which dive tec dive computer? I get asked the question all the time, whilst there are many good options out there I often recommend the Shearwater and thought I’d review why. I’ll first preface this with the style of diving I do, as this will influence your decision one way or another. I typically dive on electronic closed-circuit rebreathers, so a minimum requirement for me is the ability to use a fixed setpoint and helium based gases. If you’re thinking tec then the latter is a definite, though the ability to enable setpoint support in the future is something you should consider.

First up there is the question of why you need a tec diving computer. It might be that you have a CCR or do trimix dives, so if you’re is the case it’s easy to say you need one. Then there are other people who don’t need the full tec functions, but are likely to grow into this over time. To me these are all valid reasons why you should get a tec diving computer.

What’s out there?

Now this isn’t a round-up, so I’m not going to talk about all the computers as I’ve little and/or no experience with some of them. I will explain the logic I have for diving a Shearwater though, which is simply that it works! I bought a Shearwater Pursuit several years ago and it hasn’t missed a beat. You turn it on, battery seems to last forever and it hasn’t bent me yet. All good things in my book.

Size and Build Quality

The Predator is built tough using Delrin for the body, a thick acrylic screen and a stainless base plate. The strap is a super tough elastic material (similar to the VR3s) and appears to last for years as mind does not even show signs of wear. The original quick connect buckles were pretty ordinary and the elastic slipped, though after modifying mine with few cable ties I’ve never had a problem. I also notice that new models have changed the buckles so presumably that is no longer a problem.

At first glance they Predator appears chunky and I guess they are (particularly in height). In the water though this perception goes away and it doesn’t seem big, chunky, heavy or anything like that. The two piezo buttons on the Predator are easy to use, have no moving parts and simply work; even with thick gloves.

Screen Layout

More important to me than a glorious OLED colour screen (which the Predator has in spades) is the way the Shearwater lays out information. Clean and simple is the best way to describe it. In many ways it’s similar to the early Uwatec Aladin Pro computers that we all knew and loved (except for that beep). The Shearwater screen is laid out in three distinct rows showing:

  1. Depth, run time, next stop and stop duration
  2. Cell PPO2s, setpoint or blank (depending on CCR configuration)
  3. Mode (CCR or OC), current gas, no deco limit and time to surface.

Additional information like max depth, water temperature, CNS and much more are available at the click of a button. I like this approach as the screen does not overwhelm you, which can be a particular problem with some computers.

Decompression Model & Information

 The Predator currently uses a Bulhmann algorithm with gradient factor enhancements. This suits me fine as I like and understand the Bulhmann concepts and the gradient factors allow a lot of flexibility in the way I execute my decompression. If you want to run a VPM model today then a Shearwater is probably not the option for you, though Shearwater have indicated that a VPM model is on their roadmap.

The gradient factors applied cannot be changed during the dive, but there is a fairly innovative solution to this using the GF99 feature (check the manual for more information). I’ve not had occasion to use the feature to accelerate decompression (e.g. OC during bailout), but I have found it quite useful in understanding whether I’m actually on-gassing or decompressing. It’s particularly useful for photography, as this allows me to shoot photos during the ascent on a dive, knowing confidently that whilst I may not be decompressing, I’m not on-gassing either and incurring more decompression time.

Stop information is shown clearly, as is the total remaining time to surface. For me it’s key that this number is accurate and predictable. I typically plan my dives using PC or iphone software and when the same model and gradient factor is applied I consistently get deco information that is within a few minutes of what has been planned. Decompression information also matches my Vision within a few minutes which is nice also.

I also particularly like the decompression stop options, as you can configure it to use hard stops or a climbing ceiling. The latter matches my Vision nicely since it uses a ceiling approach to decompression.

CCR Diving

I don’t dive with any hard integration between my Inpiration Vision CCR and my Predator. I’ve been happily enough with a fixed setpoint for my backup computer, as for the most part the Vision holds setpoint quite tightly and the auto setpoint change depths are matched exactly by the Predator (user configurable). I take some solace in the fact that should I need to, I can plumb in a fischer cable on a different unit and get 3-cell real-time deco.

The Predator deals with open and closed circuit gases separated, which is a nice feature for me. It keeps the list manageable and once you click a button to go OC, the new gas list appears. The OC bailout menu click sequence is pretty easy too, so you don’t have to worry about going 3 menus back to switch to OC.

Manufacturer Support

My original Pursuit was a great computer and I dived it for years. Shearwater issued software updates to fix bugs and provide feature enhancements. Whilst they still support the product, the feature enhancements came to an end with the release of the Predator. For all purposes, it is exactly the same body as the Pursuit but with new insides (like how I’m getting technical?). For $450, Shearwater kindly takes your Pursuit and replaces the insides making it a shiny and colourful Predator with all the new software features. I congratulate Shearwater for this type of support as so often manufacturers seem to abandon their loyal customers when the next version of their product is available.

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